Pyridine → N-[5-[2-(3,5-Dimethoxyphenyl)ethyl]-1H-pyrazol-3-yl]-4-(dimethylaminomethyl)benzamide

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Reaction Steps

Oxalyl chloride (61 μl, 0.69 mmol, 1.1 eq) was added dropwise to 4-(dimethylaminomethyl)benzoic acid (113 mg, 0.63 mmol, 1 eq) in DCM (2.5 ml) containing 1 drop of DMF. After stirring at ambient temperature for 1.5 h, a solution of tert-butyl 5-amino-3-[2-(3,5-dimethoxyphenyl)ethyl]pyrazole-1-carboxylate (196 mg, 0.56 mmol, 0.9 eq) and pyridine (137 μL, 1.69 mmol, 2.70 eq) in DCM (2 ml) was added to the reaction mixture and stirring was continued at ambient temperature for a further 2 h. A solution of TFA (384 μL, 5.16 mmol, 8.25 eq) in DCM (3.5 ml) was then added and stirring was continued at ambient temperature for 18 h. The reaction mixture was concentrated and the crude product was purified by reverse-phase prep. HPLC (basic) using a gradient of acetonitrile in water containing 1% ammonium hydroxide solution. The clean fractions were taken and evaporated to afford the title compound as a colourless solid (65 mg, 25% yield); 1H NMR (399.902 MHz, DMSO) δ 2.09 (6H, s), 2.81 (4H, s), 3.38 (2H, s), 3.65 (6H, s), 6.26-6.25 (1H, m), 6.35 (2H, d), 6.40 (1H, s), 7.31 (2H, d), 7.87 (2H, d), 10.51 (1H, br.s), 12.07 (1H, br.s). MS: m/z 409 (MH+)

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